The performance and survivability of personnel in an aircraft, such as a helicopter, is a major design consideration. While protection of the pilots and other crew members is of primary importance, consideration must also be given to other personnel (e.g., assault troops and litter patients) and mechanical components (e.g., fuel cells) whose survival contributes to successful mission performance. Personnel are susceptible to all direct and secondary injury mechanisms (e.g., spall fragments and other debris) emanating from threat weapon effects, as well as from other causes including explosive removal of windows/canopies and ejection seat rockets. The separation of windows/canopies and ejection seats is particularly dangerous as separation utilizes explosives in very close proximity to the crew and other personnel on the aircraft. The separation explosive can produce explosive decompression, sound pressure and impulse, toxic fumes, and smoke, all of which can have an adverse impact on the survivability of the crew and others.
Survivability and effectiveness is of special concern in the case of helicopters such as the AH-1W and AH-1Z USMC helicopters, where a combination of factors aggravates the situation. The crew is located very close to the airframe and the helicopters have been outfitted to have improved ballistic resistance. To effect separation of canopies and fixed windows having ballistic resistance requires greater explosive force, and therefore coincident greater trauma to those onboard when these emergency egress systems are actuated.